U.S. patent number 5,078,607 [Application Number 07/654,958] was granted by the patent office on 1992-01-07 for dental implant including plural anchoring means.
This patent grant is currently assigned to Core-Vent Corporation. Invention is credited to Gerald A. Niznick.
United States Patent |
5,078,607 |
Niznick |
January 7, 1992 |
Dental implant including plural anchoring means
Abstract
A dental implant anchor includes a body portion having a first
external wall portion carrying one or more circumferential
projections separated by circumferential grooves and, below, a
second external wall portion carrying threads. The implant can
include a head portion with a smooth external wall; a through-hole
and an apical hole passing through the bottom of the implant; and
internal structure for engaging a tool for inserting the implant in
a passage formed in bone tissue. This internal structure can be in
a top portion, or in an internal passage in the body portion of the
implant. The method for forming a passage in bone tissue to receive
the implant includes forming a passage having a base with a
diameter suited to self-tapping of the threaded part of the
implant, and, above the base, a larger-diameter section to engage
frictionally the circumferential projections.
Inventors: |
Niznick; Gerald A. (Encino,
CA) |
Assignee: |
Core-Vent Corporation (Encino,
CA)
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Family
ID: |
26669497 |
Appl.
No.: |
07/654,958 |
Filed: |
February 12, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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1807 |
Jan 8, 1987 |
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Current U.S.
Class: |
433/174;
433/173 |
Current CPC
Class: |
A61C
8/0089 (20130101); A61C 8/0022 (20130101) |
Current International
Class: |
A61C
8/00 (20060101); A61C 008/00 () |
Field of
Search: |
;433/172,173,174,201.1,215 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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73177 |
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Mar 1983 |
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EP |
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2834890 |
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May 1979 |
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DE |
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3027138 |
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Dec 1981 |
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DE |
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3423752 |
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Oct 1985 |
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DE |
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98988 |
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Jan 1973 |
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JP |
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42665 |
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Oct 1976 |
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JP |
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83591 |
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Jan 1977 |
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JP |
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8601705 |
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Mar 1986 |
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WO |
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604674 |
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Sep 1978 |
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CH |
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660342 |
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Nov 1951 |
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GB |
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757487 |
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Sep 1956 |
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GB |
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937944 |
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Sep 1963 |
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GB |
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968672 |
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Sep 1964 |
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GB |
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1203093 |
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Aug 1970 |
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GB |
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1291470 |
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Oct 1972 |
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GB |
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1352188 |
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May 1974 |
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GB |
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1544784 |
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Apr 1979 |
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GB |
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1565178 |
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Apr 1980 |
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GB |
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Other References
The Journal of Prostnetic Dentistry, vol. 50, No. 1, published by
the C. V. Mosby Company, in Jul. 1983 Promotional literature for
Zest Anchor. .
Promotional literature for Scodenco O-SO Attachment System. .
Implant Prosthodontics, published by Core-Vent Corporation, 1985.
.
"Osseointegrated Titanium Implants", by T. Albrektsson et al., Acta
Orthop. Scand. 52, 155-170, 1981, pp. 167-168. .
"Osseointegrated Implants in the Treatment of the Edentulous Jaw",
by P-I Branemark et al., 1977, pp. 24, 25, 29, 31, and 109. .
Oraltronics Brochure..
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Primary Examiner: Mancene; Gene
Assistant Examiner: Lynch; Michael
Parent Case Text
This application is a continuation-in-part of application Ser. No.
07/001,807 filed Jan. 8, 1987 by Gerald A. Niznick entitled "DENTAL
IMPLANT INCLUDING PLURAL ANCHORING MEANS".
Claims
What is claimed is:
1. A substantially cylindrical dental implant anchoring means
comprising a substantially cylindrical body portion adapted to fit
in a passage formed in jawbone tissue, said body portion having an
external wall portion carrying at least two circumferential or
partially circmferential projections, each of said projections
having a size and shape adapted to engage the walls of said passage
substantially exclusively frictionally, each of said projections
having a cross-section sufficiently large to engage frictionally
the sidewalls of said passage, and to hold said anchoring means
inside said passage immediately upon insertion of said dental
implant anchoring means into said passage, each of said
circumferential projections having a groove on each side of the
projection to facilitate growth of bone tissue into said grooves to
promote anchoring of said dental implant in said passage, and,
below at least said two projections, an external wall portion
carrying thread means adapted to screw into the end of said
passage, said thread means having its axis at an oblique angle to
the longitudinal axis of said substantially cylindrical dental
implant.
2. The dental implant anchoring means of claim 1 further
comprising, above said body portion, a top portion having a smooth
external wall, said top portion slanting outwardly and upwardly
from a plane through said portion where said body portion joins
said top portion.
3. The dental implant anchoring means of claim 2 further comprising
means internal to said implant for engaging means for inserting
said implant in said passage.
4. The dental implant anchoring means of claim 3 further comprising
a through-hole passing laterally through said body portion near the
bottom of said body portion.
5. The dental implant anchoring means of claim 4 further comprising
an apical hole in the body portion of said implant extending
upwardly inside said body portion beyond said through-hole.
6. The dental implant anchoring means of claim 5 wherein each of
said projections has its circumferential axis substantially normal
to the longitudinal axis of said substantially cylindrical dental
implant.
7. The dental implant anchoring means of claim 2 wherein each of
said projections has its circumferential axis substantially normal
to the longitudinal axis of said substantially cylindrical dental
implant.
8. The dental implant anchoring means of claim 3 wherein each of
said projections has its circumferential axis substantially normal
to the longitudinal axis of said substantially cylindrical dental
implant.
9. The dental implant anchoring means of claim 4 wherein each of
said projections has its circumferential axis substantially normal
to the longitudinal axis of said substantially cylindrical dental
implant.
10. A method for inserting a dental implant including plural
anchoring means in a passage formed in jawbone tissue to receive
said dental implant anchoring means comprising forming a passage in
bone tissue having a bottom portion of a first diameter and, atop
said bottom portion, a second portion having a larger diameter;
inserting into said passage a dental implant anchoring means
comprising a body portion adapted to fit in a passage formed in
bone tissue, said body portion having an external wall portion
carrying at least one circumferential or partially circumferential
projection, said at least one projection having a size and shape
adapted to engage the walls of said passage substantially
exclusively frictionally, said projection having a cross-section
sufficiently large to engage frictionally the sidewalls of said
passage, and to hold said anchoring means inside said passage
immediately upon insertion of said dental implant anchoring means
into said passage, each of said circumferential projections having
a groove on each side of the projection to facilitate growth of
bone tissue into said grooves to promote anchoring of said dental
implant in said passage, and, below at least said one projection,
an external wall portion carrying thread means adapted to screw
into the end of said passage, said thread means having its axis at
an oblique angle to the longitudinal axis of said substantially
cylindrical dental implant, and tapping said implant anchoring
means into said passage sufficiently far that said external wall
portion carrying thread means reaches the top of the portion of the
passage having said first diameter; and the screwing said dental
implant anchoring means into said passage until said external wall
portion carrying threads is threaded into the smaller diameter
portion of said passage.
11. The method of claim 10 further comprising forming said passage
in two steps, utilizing two separate passage-forming means, the
first of said passage-forming means having a diameter appropriate
for forming the bottom portion of the passage, and the second
having a larger diameter appropriate for forming the upper portion
of said passage.
12. The method of claim 11 wherein said at least one projection has
its circumferential axis substantially normal to the longitudinal
axis of said substantially cylindrical dental implant.
13. The method of claim 10 wherein said at least one projection has
its circumferential axis substantially normal to the longitudinal
axis of said substantially cylindrical dental implant.
14. The method for inserting a dental implant including plural
anchoring means in a passage formed in jawbone tissue to receive
said dental implant anchoring means comprising:
forming a passage in bone tissue having a bottom portion of a first
diameter and, at op said bottom portion, a second portion having a
larger diameter;
inserting into said passage a dental implant anchoring means
comprising a body portion adapted to fit in said passage, said body
portion having an external wall portion carrying at least one
projection, said at least one projection having a size and shape
adapted to engage the walls of said passage substantially
exclusively frictionally, said projection having a cross-section
sufficiently large to engage frictionally the sidewalls of said
passage, and to hold said anchoring means inside said passage
immediately upon insertion of said dental implant anchoring means
into said passage, and, below said at least one projection, an
external wall portion carrying thread means adapted to screw into
the end of said passage, said thread means having its axis at an
oblique angle to the longitudinal axis of said substantially
cylindrical dental implant, and tapping said implant anchoring
means into said passage sufficiently far that said external wall
portion carrying thread means reaches the top of the portion of the
passage having said first diameter; and
then screwing said dental implant anchoring means into said passage
until said external wall portion carrying threads is threaded into
the smaller diameter portion of the passage.
15. The method of claim 14 further comprising forming said passage
in two steps, utilizing two separate passage-forming means, the
first of said passage-forming means having a diameter appropriate
for forming the bottom portion of the passage, and the second
having a larger diameter appropriate for forming the upper portion
of said passage.
Description
This invention relates to dental implant anchoring means having, on
its outer wall, a plurality of anchoring means including an outher
wall portion carrying circumferential or partially circumferential
projections and an outer wall portion carrying threads. This
anchoring means preferably includes a body portion and a top
portion with the body portion carrying the plurality of anchoring
means on its outer wall. In these preferred embodiments, the top
portion has a smooth external wall tapers upwardly and outwardly
from the body portion to a diameter that is slightly larger than
the diameter of the body portion. The top portion is sufficiently
large in diameter to insure that the top portion fits snugly
within, and tightly seals, by frictional forces, in the top of a
passage formed in bone tissue to receive the dental implant
anchoring means. Alternatively, the top portion can be of
substantially the same diameter as, or even of smaller diameter
than the body portion of the implant.
The dental implant anchoring means preferably includes, at its
distal end, a through hole extending from one side of the body
portion to the other to permit bone and associated tissue to grow
through this opening. The distal end preferably also includes a
passage at the bottom of the body portion that extends upwardly
inside the body portion a distance sufficient to permit blood and
other tissue to pass upwardly, thus allowing the anchor to seat at
the bottom of the passage formed in bone tissue to receive the
implant. Preferably, this upwardly-extending passage is less than
about one-third the length of the body portion.
The implant has an internal passage extending downwardly from the
top of the implant, and internal means for engaging and inserting
the implant into a passage formed in bone tissue to receive the
implant. The internal implant-engaging means permits insertion of
the implant in a passage formed in the bone tissue of a subject
without countersinking the upper surface of the bone tissue, where
the top portion of the implant fits upon insertion of the implant
into such a passage. This internal means is, preferably, a
wrench-engaging surface. In preferred embodiments, where the body
portion is joined to a top portion having an unthreaded, smooth
exterior wall, the internal means for implant insertion is inside
this top portion. Alternatively, this internal means can be inside
the body portion in an internal passage. Preferably, the top
portion has a hex nut configuration on its inner wall surfaces for
receiving a hex wrench, and has a cylindrically-shaped, smooth
outer wall. Alternatively, the hex nut configuration can be within,
and preferably at or near the base of the passage inside the body
portion.
In embodiments that include a top portion, the top portion is open,
and can be chamfered at its upper end, and is preferably axially
aligned with an internal passage in the body portion. The passage
can be threaded or unthreaded. This chamfered surface permits
frictional locking with any adaptor or other insert fitted into the
opening. The chamfered surface is preferably of sufficient size and
depth to afford lateral stability to any adaptor or other insert
fitted into the opening in the head portion, and forms a smooth,
easily-cleaned margin with complementary adaptors placed in the top
portion of the implant.
The anchoring means is preferably made of a titanium alloy
containing 6% by weight of aluminum and 4% by weight of vanadium;
preferably has an outside thread diameter of not more than about 3
millimeters; and preferably has projections with an outside
diameter that are at least about 0.25 millimeter larger than the
thread diameter. The anchoring means preferably has a length in the
range of about 5 to 20 millimeters.
The implant anchors of this invention are adapted for insertion in
specially-formed passages in bone tissue. Preferably, the method of
forming such a passage includes forming a passage in the bone
tissue having an upper portion with a length and a diameter
suitable for engaging the flutes or circumferential projections on
the anchor by friction, and including, at the base of the passage,
a smaller-diameter portion adapted to engage the self-tapping
threads at the bottom of the implant. The smaller-diameter portion
at the base of the opening can be formed using a first drill having
a cross-section appropriate to form a passage of this diameter and
with length that is about the same as the length of the implant to
be inserted. Thereafter, the upper portion of the passage can be
enlarged by a drill of appropriate diameter to accommodate the
fluted part of the body portion of the implant. Alternatively, the
smaller diameter and larger diameter portions of the passage can be
formed simultaneously using a drill having, at its end, a portion
of a diameter appropriate for forming the smaller diameter portion
of the passage, and an upper portion of larger diameter suitable
for forming the upper portion of the passage. The implant anchor is
tapped into the passage so formed until the bottom of the threaded
portion reaches the top of the portion of smaller diameter at the
base of the passage. Then, using an insertion tool to engage the
wrench-engaging surface inside the implant, the implant can be
screwed into the smaller-diameter part of the passage until the
threaded part of the implant reaches the bottom of the passage.
This invention can better be understood by reference to the
drawings, in which:
FIG. 1 is a perspective view of a first embodiment of the new
dental implant anchor;
FIG. 2 is a perspective view of a second embodiment of the new
dental implant anchor;
FIGS. 3A-3E show the preferred five-step method for inserting the
new dental implant anchors in the bone tissue of a subject; and
FIG. 4 shows an elevational view, in cross-section, of a third
embodiment of a new dental implant anchor.
FIG. 1 shows a first embodiment of the new dental implant anchor
generally designated 10. Anchor 10 includes body portion 11 joined
to, and surmounted by top portion 12. Body portion 11 includes
circumferential projection 16, called a flute, spaced from top
portion 12 by circumferential groove 20 on body portion 11. Below
flute 16 on body portion 11 are threads 15. At the bottom of body
portion 11 is through-hole 14 which passes axially through body
portion 11, and apical hole 13, formed at the bottom of implant 10,
and extending upwardly inside body portion 11 beyond through-hole
14.
Top portion 12 is joined to, and surmounts body portion 11. Top
portion 12 has a sidewall 17 that tapers upwardly and outwardly
from the plane, near groove 20, where body portion 11 joins top
portion 12.
Atop top portion 12 is opening 19 with wrench-engaging surface 18
on the inner wall of top portion 12. This wrench-engaging surface
18 permits threading of implant 10 into a passage formed in bone
tissue by means of a tool that fits inside implant 10, obviating
the need for any insertion tool-engaging means on the outside
surface of implant 10. Opening 19 can, in some embodiments, be in
registration with a shaft formed inside body portion 11, and the
wrench-engaging surface 18 can, in such embodiments, be at or near
the base of the shaft internal to implant 10.
FIG. 2 shows a second embodiment of the new implant, generally
designated 32, that includes head portion 30 and body portion 31.
Body portion 31 includes an external wall portion carrying a
plurality of circumferential projections 33, 34, 35, 36, 37, 38 and
39. These projections are in planes parallel to one another and are
separated from one another by grooves 40, 41, 42, 43, 44 and 45.
Below circumferential flutes 33-39 is another wall portion carrying
threads 46. The flutes facilitate seating the implant frictionally
in a passage formed in bone tissue by tapping the implant into such
a passage. Threads 46 at the bottom of body portion 31 permit the
implant to be screwed into the bottom of such a passage. Thus, the
implant can be held in place in such a passage by both the flutes
and the threads, or by either one alone if the other fails. Implant
32 also includes through hole 47 and apical opening 48 which
correspond to, and perform the same functions as openings 13 and
14, respectively, in FIG. 1.
Top portion 30 includes opening 50 and wrench-engaging surface 51,
which are identical to, and function the same as opening 19 in
wrench-engaging surface 18, respectively, in FIG. 1. As in FIG. 1,
the opening 50 may be in registration with a shaft internal to body
portion 31, and the wrench-engaging surface 51 can lie inside the
shaft instead of inside head portion 30.
FIG. 4 shows a third embodiment of the new dental implant anchoring
means. In most respects, this implant is identical to the implant
shown in FIG. 1, except that the internal wrench-engaging surface
19' lies at the bottom of the internal passage inside the implant
instead of on the internal surfaces of the top portion of the
implant. While FIG. 4 shows the internal passage, below the top
portion, to be partially threaded to receive and engage with
threaded or unthreaded inserts such as dental prostheses, the
threading is not mandatory, and the walls of the internal passage
can, in alternative embodiments, be smooth instead of threaded, or
partly threaded or partly smooth.
FIGS. 3A-3E show the preferred five-step method for inserting the
new implants into bone tissue. FIG. 3A shows the formation of a
pilot passage 60 in bone tissue 61 using a small-diameter pilot
drill 62, say a drill having a diameter of about 2 millimeters.
FIG. 3B shows using a spade drill 63 of slightly larger diameter
than the pilot drill 62, say a diameter of 2.5 millimeters, to form
a passage 64 in bone tissue 60 having a length substantially the
same as the length of the implant to be inserted, and a diameter
substantially the same as the diameter of the threaded, lower
portion of the implant. FIG. 3C shows using a spade drill 65 of
slightly larger diameter than the first spade drill 63, say
approximately 3.2 millimeters, to enlarge the upper portion of the
passage 64 formed in bone tissue in FIG. 3B to a diameter
substantially the same as the diameter of the projections or flutes
on the outer wall of the body portion above the threaded portion on
the same wall. FIG. 3D shows inserting implant 66 into the passage
formed in FIG. 3C by tapping implant 66 downwardly until the bottom
of implant 66 reaches the top of smaller-diameter portion 67 of
passage 64. FIG. 3E shows the final step of inserting implant 66
into passage 64 formed in bone tissue by ratcheting self-tapping
threads 68 at the bottom of implant 66 into smaller diameter
portion 69 of passage 64 formed in bone tissue 60.
The implants of this invention have several advantages. First, the
rounded flutes provide a surface adapted to receive coatings of
material such as hydroxyl apatite or other bone substitute
materials. The flutes also provide irregular surfaces for better
distribution of stresses on the implant from dental prostheses
attached thereto. The openings permit blood and other tissue at the
bottom of a passage formed in bone tissue to receive these implants
to pass upwardly so that the implants can seat firmly at the bottom
of such a passage. The upwardly, outwardly tapered head portion
insures that the implant, when inserted in a passage formed in bone
tissue of sufficient depth to receive the entire implant, seats
firmly and snugly at the mouth of the passage.
* * * * *